drivers/hwmon/ltc4245.c

   1 /*
   2  * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
   3  *
   4  * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  *
  10  * This driver is based on the ds1621 and ina209 drivers.
  11  *
  12  * Datasheet:
  13  * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/err.h>
  20 #include <linux/slab.h>
  21 #include <linux/i2c.h>
  22 #include <linux/hwmon.h>
  23 #include <linux/hwmon-sysfs.h>
  24 #include <linux/i2c/ltc4245.h>
  25
  26 /* Here are names of the chip's registers (a.k.a. commands) */
  27 enum ltc4245_cmd {
  28         LTC4245_STATUS                  = 0x00, /* readonly */
  29         LTC4245_ALERT                   = 0x01,
  30         LTC4245_CONTROL                 = 0x02,
  31         LTC4245_ON                      = 0x03,
  32         LTC4245_FAULT1                  = 0x04,
  33         LTC4245_FAULT2                  = 0x05,
  34         LTC4245_GPIO                    = 0x06,
  35         LTC4245_ADCADR                  = 0x07,
  36
  37         LTC4245_12VIN                   = 0x10,
  38         LTC4245_12VSENSE                = 0x11,
  39         LTC4245_12VOUT                  = 0x12,
  40         LTC4245_5VIN                    = 0x13,
  41         LTC4245_5VSENSE                 = 0x14,
  42         LTC4245_5VOUT                   = 0x15,
  43         LTC4245_3VIN                    = 0x16,
  44         LTC4245_3VSENSE                 = 0x17,
  45         LTC4245_3VOUT                   = 0x18,
  46         LTC4245_VEEIN                   = 0x19,
  47         LTC4245_VEESENSE                = 0x1a,
  48         LTC4245_VEEOUT                  = 0x1b,
  49         LTC4245_GPIOADC                 = 0x1c,
  50 };
  51
  52 struct ltc4245_data {
  53         struct device *hwmon_dev;
  54
  55         struct mutex update_lock;
  56         bool valid;
  57         unsigned long last_updated; /* in jiffies */
  58
  59         /* Control registers */
  60         u8 cregs[0x08];
  61
  62         /* Voltage registers */
  63         u8 vregs[0x0d];
  64
  65         /* GPIO ADC registers */
  66         bool use_extra_gpios;
  67         int gpios[3];
  68 };
  69
  70 /*
  71  * Update the readings from the GPIO pins. If the driver has been configured to
  72  * sample all GPIO's as analog voltages, a round-robin sampling method is used.
  73  * Otherwise, only the configured GPIO pin is sampled.
  74  *
  75  * LOCKING: must hold data->update_lock
  76  */
  77 static void ltc4245_update_gpios(struct device *dev)
  78 {
  79         struct i2c_client *client = to_i2c_client(dev);
  80         struct ltc4245_data *data = i2c_get_clientdata(client);
  81         u8 gpio_curr, gpio_next, gpio_reg;
  82         int i;
  83
  84         /* no extra gpio support, we're basically done */
  85         if (!data->use_extra_gpios) {
  86                 data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
  87                 return;
  88         }
  89
  90         /*
  91          * If the last reading was too long ago, then we mark all old GPIO
  92          * readings as stale by setting them to -EAGAIN
  93          */
  94         if (time_after(jiffies, data->last_updated + 5 * HZ)) {
  95                 dev_dbg(&client->dev, "Marking GPIOs invalid\n");
  96                 for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
  97                         data->gpios[i] = -EAGAIN;
  98         }
  99
 100         /*
 101          * Get the current GPIO pin
 102          *
 103          * The datasheet calls these GPIO[1-3], but we'll calculate the zero
 104          * based array index instead, and call them GPIO[0-2]. This is much
 105          * easier to think about.
 106          */
 107         gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
 108         if (gpio_curr > 0)
 109                 gpio_curr -= 1;
 110
 111         /* Read the GPIO voltage from the GPIOADC register */
 112         data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
 113
 114         /* Find the next GPIO pin to read */
 115         gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
 116
 117         /*
 118          * Calculate the correct setting for the GPIO register so it will
 119          * sample the next GPIO pin
 120          */
 121         gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
 122
 123         /* Update the GPIO register */
 124         i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
 125
 126         /* Update saved data */
 127         data->cregs[LTC4245_GPIO] = gpio_reg;
 128 }
 129
 130 static struct ltc4245_data *ltc4245_update_device(struct device *dev)
 131 {
 132         struct i2c_client *client = to_i2c_client(dev);
 133         struct ltc4245_data *data = i2c_get_clientdata(client);
 134         s32 val;
 135         int i;
 136
 137         mutex_lock(&data->update_lock);
 138
 139         if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
 140
 141                 dev_dbg(&client->dev, "Starting ltc4245 update\n");
 142
 143                 /* Read control registers -- 0x00 to 0x07 */
 144                 for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
 145                         val = i2c_smbus_read_byte_data(client, i);
 146                         if (unlikely(val < 0))
 147                                 data->cregs[i] = 0;
 148                         else
 149                                 data->cregs[i] = val;
 150                 }
 151
 152                 /* Read voltage registers -- 0x10 to 0x1c */
 153                 for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
 154                         val = i2c_smbus_read_byte_data(client, i+0x10);
 155                         if (unlikely(val < 0))
 156                                 data->vregs[i] = 0;
 157                         else
 158                                 data->vregs[i] = val;
 159                 }
 160
 161                 /* Update GPIO readings */
 162                 ltc4245_update_gpios(dev);
 163
 164                 data->last_updated = jiffies;
 165                 data->valid = 1;
 166         }
 167
 168         mutex_unlock(&data->update_lock);
 169
 170         return data;
 171 }
 172
 173 /* Return the voltage from the given register in millivolts */
 174 static int ltc4245_get_voltage(struct device *dev, u8 reg)
 175 {
 176         struct ltc4245_data *data = ltc4245_update_device(dev);
 177         const u8 regval = data->vregs[reg - 0x10];
 178         u32 voltage = 0;
 179
 180         switch (reg) {
 181         case LTC4245_12VIN:
 182         case LTC4245_12VOUT:
 183                 voltage = regval * 55;
 184                 break;
 185         case LTC4245_5VIN:
 186         case LTC4245_5VOUT:
 187                 voltage = regval * 22;
 188                 break;
 189         case LTC4245_3VIN:
 190         case LTC4245_3VOUT:
 191                 voltage = regval * 15;
 192                 break;
 193         case LTC4245_VEEIN:
 194         case LTC4245_VEEOUT:
 195                 voltage = regval * -55;
 196                 break;
 197         case LTC4245_GPIOADC:
 198                 voltage = regval * 10;
 199                 break;
 200         default:
 201                 /* If we get here, the developer messed up */
 202                 WARN_ON_ONCE(1);
 203                 break;
 204         }
 205
 206         return voltage;
 207 }
 208
 209 /* Return the current in the given sense register in milliAmperes */
 210 static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
 211 {
 212         struct ltc4245_data *data = ltc4245_update_device(dev);
 213         const u8 regval = data->vregs[reg - 0x10];
 214         unsigned int voltage;
 215         unsigned int curr;
 216
 217         /* The strange looking conversions that follow are fixed-point
 218          * math, since we cannot do floating point in the kernel.
 219          *
 220          * Step 1: convert sense register to microVolts
 221          * Step 2: convert voltage to milliAmperes
 222          *
 223          * If you play around with the V=IR equation, you come up with
 224          * the following: X uV / Y mOhm == Z mA
 225          *
 226          * With the resistors that are fractions of a milliOhm, we multiply
 227          * the voltage and resistance by 10, to shift the decimal point.
 228          * Now we can use the normal division operator again.
 229          */
 230
 231         switch (reg) {
 232         case LTC4245_12VSENSE:
 233                 voltage = regval * 250; /* voltage in uV */
 234                 curr = voltage / 50; /* sense resistor 50 mOhm */
 235                 break;
 236         case LTC4245_5VSENSE:
 237                 voltage = regval * 125; /* voltage in uV */
 238                 curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
 239                 break;
 240         case LTC4245_3VSENSE:
 241                 voltage = regval * 125; /* voltage in uV */
 242                 curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
 243                 break;
 244         case LTC4245_VEESENSE:
 245                 voltage = regval * 250; /* voltage in uV */
 246                 curr = voltage / 100; /* sense resistor 100 mOhm */
 247                 break;
 248         default:
 249                 /* If we get here, the developer messed up */
 250                 WARN_ON_ONCE(1);
 251                 curr = 0;
 252                 break;
 253         }
 254
 255         return curr;
 256 }
 257
 258 static ssize_t ltc4245_show_voltage(struct device *dev,
 259                                     struct device_attribute *da,
 260                                     char *buf)
 261 {
 262         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 263         const int voltage = ltc4245_get_voltage(dev, attr->index);
 264
 265         return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
 266 }
 267
 268 static ssize_t ltc4245_show_current(struct device *dev,
 269                                     struct device_attribute *da,
 270                                     char *buf)
 271 {
 272         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 273         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 274
 275         return snprintf(buf, PAGE_SIZE, "%u\n", curr);
 276 }
 277
 278 static ssize_t ltc4245_show_power(struct device *dev,
 279                                   struct device_attribute *da,
 280                                   char *buf)
 281 {
 282         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 283         const unsigned int curr = ltc4245_get_current(dev, attr->index);
 284         const int output_voltage = ltc4245_get_voltage(dev, attr->index+1);
 285
 286         /* current in mA * voltage in mV == power in uW */
 287         const unsigned int power = abs(output_voltage * curr);
 288
 289         return snprintf(buf, PAGE_SIZE, "%u\n", power);
 290 }
 291
 292 static ssize_t ltc4245_show_alarm(struct device *dev,
 293                                           struct device_attribute *da,
 294                                           char *buf)
 295 {
 296         struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
 297         struct ltc4245_data *data = ltc4245_update_device(dev);
 298         const u8 reg = data->cregs[attr->index];
 299         const u32 mask = attr->nr;
 300
 301         return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
 302 }
 303
 304 static ssize_t ltc4245_show_gpio(struct device *dev,
 305                                  struct device_attribute *da,
 306                                  char *buf)
 307 {
 308         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 309         struct ltc4245_data *data = ltc4245_update_device(dev);
 310         int val = data->gpios[attr->index];
 311
 312         /* handle stale GPIO's */
 313         if (val < 0)
 314                 return val;
 315
 316         /* Convert to millivolts and print */
 317         return snprintf(buf, PAGE_SIZE, "%u\n", val * 10);
 318 }
 319
 320 /* These macros are used below in constructing device attribute objects
 321  * for use with sysfs_create_group() to make a sysfs device file
 322  * for each register.
 323  */
 324
 325 #define LTC4245_VOLTAGE(name, ltc4245_cmd_idx) \
 326         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 327         ltc4245_show_voltage, NULL, ltc4245_cmd_idx)
 328
 329 #define LTC4245_CURRENT(name, ltc4245_cmd_idx) \
 330         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 331         ltc4245_show_current, NULL, ltc4245_cmd_idx)
 332
 333 #define LTC4245_POWER(name, ltc4245_cmd_idx) \
 334         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 335         ltc4245_show_power, NULL, ltc4245_cmd_idx)
 336
 337 #define LTC4245_ALARM(name, mask, reg) \
 338         static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \
 339         ltc4245_show_alarm, NULL, (mask), reg)
 340
 341 #define LTC4245_GPIO_VOLTAGE(name, gpio_num) \
 342         static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 343         ltc4245_show_gpio, NULL, gpio_num)
 344
 345 /* Construct a sensor_device_attribute structure for each register */
 346
 347 /* Input voltages */
 348 LTC4245_VOLTAGE(in1_input,                      LTC4245_12VIN);
 349 LTC4245_VOLTAGE(in2_input,                      LTC4245_5VIN);
 350 LTC4245_VOLTAGE(in3_input,                      LTC4245_3VIN);
 351 LTC4245_VOLTAGE(in4_input,                      LTC4245_VEEIN);
 352
 353 /* Input undervoltage alarms */
 354 LTC4245_ALARM(in1_min_alarm,    (1 << 0),       LTC4245_FAULT1);
 355 LTC4245_ALARM(in2_min_alarm,    (1 << 1),       LTC4245_FAULT1);
 356 LTC4245_ALARM(in3_min_alarm,    (1 << 2),       LTC4245_FAULT1);
 357 LTC4245_ALARM(in4_min_alarm,    (1 << 3),       LTC4245_FAULT1);
 358
 359 /* Currents (via sense resistor) */
 360 LTC4245_CURRENT(curr1_input,                    LTC4245_12VSENSE);
 361 LTC4245_CURRENT(curr2_input,                    LTC4245_5VSENSE);
 362 LTC4245_CURRENT(curr3_input,                    LTC4245_3VSENSE);
 363 LTC4245_CURRENT(curr4_input,                    LTC4245_VEESENSE);
 364
 365 /* Overcurrent alarms */
 366 LTC4245_ALARM(curr1_max_alarm,  (1 << 4),       LTC4245_FAULT1);
 367 LTC4245_ALARM(curr2_max_alarm,  (1 << 5),       LTC4245_FAULT1);
 368 LTC4245_ALARM(curr3_max_alarm,  (1 << 6),       LTC4245_FAULT1);
 369 LTC4245_ALARM(curr4_max_alarm,  (1 << 7),       LTC4245_FAULT1);
 370
 371 /* Output voltages */
 372 LTC4245_VOLTAGE(in5_input,                      LTC4245_12VOUT);
 373 LTC4245_VOLTAGE(in6_input,                      LTC4245_5VOUT);
 374 LTC4245_VOLTAGE(in7_input,                      LTC4245_3VOUT);
 375 LTC4245_VOLTAGE(in8_input,                      LTC4245_VEEOUT);
 376
 377 /* Power Bad alarms */
 378 LTC4245_ALARM(in5_min_alarm,    (1 << 0),       LTC4245_FAULT2);
 379 LTC4245_ALARM(in6_min_alarm,    (1 << 1),       LTC4245_FAULT2);
 380 LTC4245_ALARM(in7_min_alarm,    (1 << 2),       LTC4245_FAULT2);
 381 LTC4245_ALARM(in8_min_alarm,    (1 << 3),       LTC4245_FAULT2);
 382
 383 /* GPIO voltages */
 384 LTC4245_GPIO_VOLTAGE(in9_input,                 0);
 385 LTC4245_GPIO_VOLTAGE(in10_input,                1);
 386 LTC4245_GPIO_VOLTAGE(in11_input,                2);
 387
 388 /* Power Consumption (virtual) */
 389 LTC4245_POWER(power1_input,                     LTC4245_12VSENSE);
 390 LTC4245_POWER(power2_input,                     LTC4245_5VSENSE);
 391 LTC4245_POWER(power3_input,                     LTC4245_3VSENSE);
 392 LTC4245_POWER(power4_input,                     LTC4245_VEESENSE);
 393
 394 /* Finally, construct an array of pointers to members of the above objects,
 395  * as required for sysfs_create_group()
 396  */
 397 static struct attribute *ltc4245_std_attributes[] = {
 398         &sensor_dev_attr_in1_input.dev_attr.attr,
 399         &sensor_dev_attr_in2_input.dev_attr.attr,
 400         &sensor_dev_attr_in3_input.dev_attr.attr,
 401         &sensor_dev_attr_in4_input.dev_attr.attr,
 402
 403         &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 404         &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 405         &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 406         &sensor_dev_attr_in4_min_alarm.dev_attr.attr,
 407
 408         &sensor_dev_attr_curr1_input.dev_attr.attr,
 409         &sensor_dev_attr_curr2_input.dev_attr.attr,
 410         &sensor_dev_attr_curr3_input.dev_attr.attr,
 411         &sensor_dev_attr_curr4_input.dev_attr.attr,
 412
 413         &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 414         &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
 415         &sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
 416         &sensor_dev_attr_curr4_max_alarm.dev_attr.attr,
 417
 418         &sensor_dev_attr_in5_input.dev_attr.attr,
 419         &sensor_dev_attr_in6_input.dev_attr.attr,
 420         &sensor_dev_attr_in7_input.dev_attr.attr,
 421         &sensor_dev_attr_in8_input.dev_attr.attr,
 422
 423         &sensor_dev_attr_in5_min_alarm.dev_attr.attr,
 424         &sensor_dev_attr_in6_min_alarm.dev_attr.attr,
 425         &sensor_dev_attr_in7_min_alarm.dev_attr.attr,
 426         &sensor_dev_attr_in8_min_alarm.dev_attr.attr,
 427
 428         &sensor_dev_attr_in9_input.dev_attr.attr,
 429
 430         &sensor_dev_attr_power1_input.dev_attr.attr,
 431         &sensor_dev_attr_power2_input.dev_attr.attr,
 432         &sensor_dev_attr_power3_input.dev_attr.attr,
 433         &sensor_dev_attr_power4_input.dev_attr.attr,
 434
 435         NULL,
 436 };
 437
 438 static struct attribute *ltc4245_gpio_attributes[] = {
 439         &sensor_dev_attr_in10_input.dev_attr.attr,
 440         &sensor_dev_attr_in11_input.dev_attr.attr,
 441         NULL,
 442 };
 443
 444 static const struct attribute_group ltc4245_std_group = {
 445         .attrs = ltc4245_std_attributes,
 446 };
 447
 448 static const struct attribute_group ltc4245_gpio_group = {
 449         .attrs = ltc4245_gpio_attributes,
 450 };
 451
 452 static int ltc4245_sysfs_create_groups(struct i2c_client *client)
 453 {
 454         struct ltc4245_data *data = i2c_get_clientdata(client);
 455         struct device *dev = &client->dev;
 456         int ret;
 457
 458         /* register the standard sysfs attributes */
 459         ret = sysfs_create_group(&dev->kobj, &ltc4245_std_group);
 460         if (ret) {
 461                 dev_err(dev, "unable to register standard attributes\n");
 462                 return ret;
 463         }
 464
 465         /* if we're using the extra gpio support, register it's attributes */
 466         if (data->use_extra_gpios) {
 467                 ret = sysfs_create_group(&dev->kobj, &ltc4245_gpio_group);
 468                 if (ret) {
 469                         dev_err(dev, "unable to register gpio attributes\n");
 470                         sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
 471                         return ret;
 472                 }
 473         }
 474
 475         return 0;
 476 }
 477
 478 static void ltc4245_sysfs_remove_groups(struct i2c_client *client)
 479 {
 480         struct ltc4245_data *data = i2c_get_clientdata(client);
 481         struct device *dev = &client->dev;
 482
 483         if (data->use_extra_gpios)
 484                 sysfs_remove_group(&dev->kobj, &ltc4245_gpio_group);
 485
 486         sysfs_remove_group(&dev->kobj, &ltc4245_std_group);
 487 }
 488
 489 static bool ltc4245_use_extra_gpios(struct i2c_client *client)
 490 {
 491         struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
 492 #ifdef CONFIG_OF
 493         struct device_node *np = client->dev.of_node;
 494 #endif
 495
 496         /* prefer platform data */
 497         if (pdata)
 498                 return pdata->use_extra_gpios;
 499
 500 #ifdef CONFIG_OF
 501         /* fallback on OF */
 502         if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
 503                 return true;
 504 #endif
 505
 506         return false;
 507 }
 508
 509 static int ltc4245_probe(struct i2c_client *client,
 510                          const struct i2c_device_id *id)
 511 {
 512         struct i2c_adapter *adapter = client->adapter;
 513         struct ltc4245_data *data;
 514         int ret;
 515
 516         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 517                 return -ENODEV;
 518
 519         data = kzalloc(sizeof(*data), GFP_KERNEL);
 520         if (!data) {
 521                 ret = -ENOMEM;
 522                 goto out_kzalloc;
 523         }
 524
 525         i2c_set_clientdata(client, data);
 526         mutex_init(&data->update_lock);
 527         data->use_extra_gpios = ltc4245_use_extra_gpios(client);
 528
 529         /* Initialize the LTC4245 chip */
 530         i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
 531         i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
 532
 533         /* Register sysfs hooks */
 534         ret = ltc4245_sysfs_create_groups(client);
 535         if (ret)
 536                 goto out_sysfs_create_groups;
 537
 538         data->hwmon_dev = hwmon_device_register(&client->dev);
 539         if (IS_ERR(data->hwmon_dev)) {
 540                 ret = PTR_ERR(data->hwmon_dev);
 541                 goto out_hwmon_device_register;
 542         }
 543
 544         return 0;
 545
 546 out_hwmon_device_register:
 547         ltc4245_sysfs_remove_groups(client);
 548 out_sysfs_create_groups:
 549         kfree(data);
 550 out_kzalloc:
 551         return ret;
 552 }
 553
 554 static int ltc4245_remove(struct i2c_client *client)
 555 {
 556         struct ltc4245_data *data = i2c_get_clientdata(client);
 557
 558         hwmon_device_unregister(data->hwmon_dev);
 559         ltc4245_sysfs_remove_groups(client);
 560         kfree(data);
 561
 562         return 0;
 563 }
 564
 565 static const struct i2c_device_id ltc4245_id[] = {
 566         { "ltc4245", 0 },
 567         { }
 568 };
 569 MODULE_DEVICE_TABLE(i2c, ltc4245_id);
 570
 571 /* This is the driver that will be inserted */
 572 static struct i2c_driver ltc4245_driver = {
 573         .driver = {
 574                 .name   = "ltc4245",
 575         },
 576         .probe          = ltc4245_probe,
 577         .remove         = ltc4245_remove,
 578         .id_table       = ltc4245_id,
 579 };
 580
 581 static int __init ltc4245_init(void)
 582 {
 583         return i2c_add_driver(&ltc4245_driver);
 584 }
 585
 586 static void __exit ltc4245_exit(void)
 587 {
 588         i2c_del_driver(&ltc4245_driver);
 589 }
 590
 591 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
 592 MODULE_DESCRIPTION("LTC4245 driver");
 593 MODULE_LICENSE("GPL");
 594
 595 module_init(ltc4245_init);
 596 module_exit(ltc4245_exit);